Russia withdrew from the Black Sea grain deal that ensured the safe export of Ukrainian grains because the agreement lost its meaning, President Vladimir Putin wrote in an article published early on Monday.

"The continuation of the 'grain deal' - which did not justify its humanitarian purpose - has lost its meaning," Putin said, according to the article on the Kremlin's website.

Saying that Russia's conditions for the extension had been ignored, Moscow last week quit the deal which had allowed Ukraine a year ago to export grain from its Black Sea ports, despite the war, to alleviate a global food crisis.

The key demands Putin presented last week for Moscow to return to the deal, however, did not directly refer to humanitarian purposes.

After quitting the deal, Russia has been pounding Ukrainian food-exporting ports nearly on a daily basis. An attack on Sunday on the southern port of Odesa killed one person and injured scores more.

Writing ahead of the second Russia-Africa summit that will take place in St. Petersburg on Thursday and Friday, Putin said that Russia expects a record harvest this year.

"I want to assure that our country is able to replace Ukrainian grain both commercially and free of charge, especially since we again expect a record harvest this year," Putin said.

Russia and the West have been increasingly vying for influence in Africa. Although Moscow has so far invested very little there, according to data from the United Nations, Russia has been on a diplomatic push to win the continent's support.

During a U.N. vote in March 2022 to condemn Russia's invasion of Ukraine, 28 African nations voted in favour of the resolution, but 25 either voted to abstain or did not vote at all.

"Russia will continue to vigorously work on organising the supply of grain, food, fertilizers and more to Africa: we highly value and continue to dynamically develop the entire range of economic ties with Africa," Putin wrote.

(Reporting by Lidia Kelly in Melbourne; Editing by Cynthia Osterman)